One-pack moisture-curing epoxy resin composition

ABSTRACT

A one-pack moisture-curing epoxy resin composition which can be cured at ordinary temperatures and is improved in storage stability without impairing the quickness of curing, i.e., is excellent in two properties incompatible with each other. This composition includes one ore more members selected from the group consisting of vinyl carboxylates of the general formula (1) and epoxy-containing silyl compounds of the general formula (2), one or more members selected from the group consisting of ketimines and oxazolidines, and an epoxy resin. (1) [In the general formula (1), R 1 , R 2 , R 3 , and R 4  are each independently hydrogen or an organic group; and n is an integer of 1 or above] (2) [In the general formula (2), R 5  and R 6  are each independently alkyl; R 7  is an epoxy-containing organic group; and n is an integer of 1 to 3]

TECHNICAL FIELD

[0001] The present invention relates to a one-pack moisture curableepoxy resin composition having excellent curing properties and goodstorage stability. Particularly, the present invention relates to aone-pack moisture curable epoxy resin composition having excellentcuring properties and good storage stability and suitable as a one-packroom-temperature curable epoxy adhesive, one-pack room-temperaturecurable epoxy putty material, one-pack room-temperature curable epoxypaint, one-pack room-temperature curable epoxy coating material andone-pack room-temperature curable epoxy potting material.

BACKGROUND ART

[0002] An epoxy resin composition is excellent in physical strength andadhesion and has been widely used as an adhesive, putty material, paintand coating material. Since the conventional epoxy resin compositionuses a highly reactive amine compound as a hardener, it is a two-packtype characterized in that an epoxy resin and the hardener component aremixed together right before use of the two-pack type. However, since thetwo-pack epoxy resin composition requires such operations as measuringand mixing, it has poor workability. Further, due to complication of theoperations, the two-pack epoxy resin composition also has problems suchas a measuring error and inadequate mixing. In addition, the two-packepoxy resin composition also has a problem that time in which it can beused is limited since a chemical reaction in the two-pack type isinitiated by mixing.

[0003] Under the circumstances, a variety of studies on a one-pack epoxyresin composition have been made, and a number of techniques for aone-pack epoxy resin composition using a moisture hydrolyzable latenthardener, notably a ketimine compound and an oxazolidine compound, areknown. In particular, from an industrial standpoint, a variety oftechniques for a one-pack epoxy resin composition using a ketiminecompound obtained from methyl isobutyl ketone as a carbonyl compoundhave been disclosed.

[0004] The ketimine compound and the oxazolidine compound are well-knownas a latent hardener for an epoxy resin and an isocyanate-terminatedurethane polymer. Hereinafter, a reaction mechanism of a compositioncomprising the ketimine compound or oxazolidine compound as a latenthardener and an epoxy resin will be described. Firstly, as a firstreaction, the ketimine compound reacts with moisture in the air and ishydrolyzed so as to produce a primary amine compound having activehydrogen. The oxazolidine compound reacts with moisture in the air so asto produce a secondary amino alcohol. Thus, the first reaction is aprocess in which the latent hardener is hydrolyzed by moisture.Subsequently, as a second reaction, the produced amine compound havingactive hydrogen reacts with the epoxy resin, and by this mechanism, theepoxy resin composition is cured. Hence, the second reaction is aprocess in which the hydrolyzed latent hardener chemically reacts withthe epoxy resin. That is, the reaction mechanism of the compositioncomprising the latent hardener and the epoxy resin is a two-stepreaction comprising the reaction of the latent hardener with moistureand the reaction of the amine compound with the epoxy resin. In thesetwo processes, the most important points with respect to thecompositions comprising these latent hardeners and the epoxy resin arethat (1) the quicker the hydrolysis of the latent hardener such as theketimine compound proceeds, quicker-curability can be obtained and that(2) the higher the reactivity of the amine compound resulting from thehydrolysis, the more easily physical properties such as quick curabilityand high strength are obtained. However, when a ketimine compound whichis hydrolyzed quickly is used, the ketimine compound is liable to behydrolyzed during production or storage of the one-pack epoxy resin, sothat it becomes difficult to obtain good storage stability. Hence, itwas the limitation of the prior art that it could not help but relyingon means using a ketimine compound obtained from an amine compoundhaving high reactivity with the epoxy resin and having lowhydrolyzability, in consideration of storage stability. Thus, sincethere is a dilemma that an improvement in quick curability causesimpairment of storage stability, a technique of achieving practicalquick curability and practical storage stability simultaneously in thecomposition comprising the ketimine compound and the epoxy resin is notyet found at all.

[0005] Meanwhile, recently, a technique of improving storage stabilityby use of a specific ketimine compound obtained from a carbonyl compoundhaving steric hindrance is disclosed in WO98/31722. The specificketimine compound has low hydrolyzability since water hardly makescontact with a site showing hydrolyzability due to its steric structure.Therefore, the ketimine compound has the conventional problem thatalthough it can impart good storage stability, it fails to impart goodcuring properties such as quick curability. That is, when the specificketimine compound is used, there arises a problem that curing of anepoxy resin composition proceeds slowly, so that initial adhesivestrength and mechanical strength are slow to become in effect. It takeslong-time curing to attain practicable physical properties, so that theketimine compound is practically unsatisfactory. Consequently, even thistechnique is not a technique capable of achieving practical curingproperties and practical storage stability simultaneously. That is, itis a technical means which is an extension of the prior art.

[0006] Thus, if a composition having excellent storage stability andexcellent curing properties is found out of compositions comprising aketimine compound or oxazolidine compound as a latent hardener and anepoxy resin, it becomes a fundamental technique for an adhesive, puttymaterial, paint, coating material and potting material using them, sothat usefulness of such a composition in industry is significantlyimproved.

[0007] Under the circumstances, an object of the present invention is toprovide a one-pack moisture curable epoxy resin composition which can becured at room temperature, shows balanced contradictory properties,i.e., has significantly excellent storage stability without impairingcurability, and also has excellent deep curability.

DISCLOSURE OF THE INVENTION

[0008] The present inventors have made intensive studies so as toachieve the above object. As a result, they have found that a one-packmoisture curable epoxy resin composition comprising a vinyl carboxylatecompound or a silane compound having an epoxy group and a ketiminecompound or an oxazolidine compound shows significantly excellentstorage stability. They have also found that when a vinyl carboxylatecompound or a silyl compound having an epoxy group is added to aone-pack moisture curable epoxy resin composition containing a ketiminecompound or oxazolidine compound which is hydrolyzed by moisture in theair so as to produce an amine compound, storage stability can be furtherimproved without impairing curing properties such as rises of adhesiveproperty and mechanical strength. Further, they have found that an epoxyresin composition containing a silyl compound having an epoxy group hasexceptionally excellent deep curability. It has been confirmed that thetechnique is a function of not inhibiting having but achieving the abovepractical curing properties and storage stability simultaneously. Morespecifically, although there has been a dilemma in the prior art thatstorage stability must be improved at the sacrifice of curingproperties, the above technique has been confirmed to be a technique foreliminating the dilemma.

[0009] That is, the invention of the present application is based on aneffect that the epoxy-group-containing silyl compound added to the aboveepoxy resin composition removes water entering the composition duringits production or storage in a container before the ketimine compound oroxazolidine compound reacts with the water so as to allow the ketiminecompound or oxazolidine compound to exist stably and an effect that theepoxy group reacts with the amine compound so as to improve storagestability without impairing physical properties of a cured product.Further, the invention of the present application is also based on aneffect that the vinyl carboxylate compound added to the above epoxyresin composition blocks active hydrogen of the amine compound resultingfrom hydrolysis of the ketimine compound or oxazolidine compound duringstorage of the composition in a container so as to further improvestorage stability. These two techniques are techniques for achieving thedesired object of having practical curing properties and excellentstorage stability. The techniques act on the different reactionsconstituting the two-step reaction of the ketimine compound oroxazolidine compound with the epoxy resin, and each of the techniques isstill effective alone in improving storage stability. Further, since thetechniques exhibit their effects of improving storage stability in thedifferent reactions steps without offsetting the effects, storagestability is further improved by using these two techniquessimultaneously.

[0010] Based on these findings, the present inventors have widelystudied types of compounds having such properties, amounts of thesecompounds to be mixed with the epoxy resin, and techniques ofsynthesizing these compounds. As a result, they have succeeded indevelopment of a one-pack moisture curable epoxy resin composition whichcan be used without any problems even after long-time storage withoutimpairing the speeds of rises of initial adhesive strength, adhesivestrength and mechanical strength and have completed the presentinvention.

[0011] As means of the present invention for achieving the above object,a first invention is a one-pack moisture curable epoxy resin compositioncomprising:

[0012] one or two or more compounds selected from the group consistingof a vinyl carboxylate compound represented by the following chemicalformula (1) and a silyl compound represented by the following chemicalformula (2) which has an epoxy group in an organic group, one or two ormore compounds selected from the group consisting of a ketimine compoundrepresented by the following chemical formula (4) which is obtained byreaction of a carbonyl compound represented by the following chemicalformula (3) with an amine compound having a primary amino group and anoxazolidine compound represented by the following chemical formula (5)which is obtained by dehydration condensation of a carbonyl compound andan aminoalcohol compound, and an epoxy resin:

[0013] wherein R₁, R₂, R₃ and R₄ are each a hydrogen atom or an organicgroup and they may be the same or different, and n is an integer of 1 ormore,

[0014] wherein R₅ and R₆ are each an alkyl group and they may be thesame or different,

[0015] R₇ is an organic group having an epoxy group,

[0016] n is an integer of 1 to 3,

[0017] wherein R₈ and R₉ are each an alkyl group and they may be thesame or different,

[0018] wherein R₁₀ is a residue excluding a primary amino group of anamine compound,

[0019] R₈ and R₉ are each an alkyl group and they may be the same ordifferent, and

[0020] n is an integer of 1 or more, and

[0021] wherein R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are each a hydrogen atom or anorganic group.

[0022] A silyl compound having an epoxy group in the present inventionis a compound represented by the above chemical formula (2) which has ahydrolyzable alkoxysilyl group comprising an Si—O bond and an epoxygroup. The alkoxysilyl site causes a dealcoholization reaction withwater, thereby consuming the water. The silyl compound reacts with andconsumes a small amount of water entering the composition system duringstorage before the ketimine compound reacts with the water so as toprevent hydrolysis of the ketimine compound. Since it is prevented thatthe ketimine compound is hydrolyzed during storage and produces an aminecompound, storage stability is improved. The silyl compound also reactswith water quickly upon use of the adhesive composition. In that case,however, since a large amount of water enters the system, the ketiminecompound represented by the above chemical formula (4) in the presentinvention also reacts with water quickly due to its highhydrolyzability. That is, this implies that the composition of thepresent invention does not require long-time curing so as to obtainpracticable physical properties.

[0023] Further, in such a silyl compound, the epoxy group also acts as areactive site in addition to the hydrolyzable S—O bond. Hence, it hasmore crosslinkable sites in a molecule. Accordingly, a more complicatedcrosslinked structure is formed more quickly, and curing occurs in adeeper portion even after curing over a predetermined time period. Thatis, this implies that it has excellent deep curability. The technique isa function of not inhibiting having but achieving the above practicalcuring properties and storage stability simultaneously.

[0024] A vinyl carboxylate compound used in the present invention is acompound represented by the above chemical formula (1) which has aC═C—O—C═O bond. The site reacts with an amine compound so as to producean amide compound. The vinyl carboxylate compound reacts with a smallamount of amine compound resulting from hydrolysis of the ketiminecompound or oxazolidine compound by a small amount of water entering thecomposition system during storage so as to produce an amide compoundhaving low activity with the epoxy resin, thereby improving storagestability. The vinyl carboxylate compound also reacts with the aminecompound upon use of the adhesive composition. However, since its amountis small whereas the amount of the amine compound resulting from thehydrolysis is large, it has no influence on curing properties. That is,this implies that storage stability can be improved without impairingcuring properties upon use.

[0025] By incorporating the above vinyl carboxylate compound into theone-pack epoxy resin composition, storage stability could be improveddramatically.

[0026] A ketimine compound used in the present invention is a compoundrepresented by the above chemical formula (4) which has a hydrolyzableC═N double bond. The site reacts with water so as to be hydrolyzed intoan amine compound having a primary amino group and a carbonyl compoundhaving two same or different alkyl groups. In the one-pack moisturecurable epoxy resin composition, the produced amine compound reacts withthe epoxy resin so as to cure the composition.

[0027] An oxazolidine compound used in the present invention is ahydrolyzable cyclic compound represented by the above chemical formula(5) which has an O atom and an N atom on the same carbon. The sitereacts with water so as to be hydrolyzed into a secondary aminoalcoholand a carbonyl compound having two same or different alkyl groups. Inthe one-pack moisture curable epoxy resin composition, the producedamine compound reacts with the epoxy resin so as to cure thecomposition.

[0028] A second invention is a one-pack moisture curable epoxy resincomposition comprising:

[0029] a vinyl carboxylate compound represented by the above chemicalformula (1),

[0030] one or two or more compounds selected from the group consistingof a ketimine compound represented by the above chemical formula (4)which is obtained by reaction of a carbonyl compound represented by theabove chemical formula (3) with an amine compound having a primary aminogroup and an oxazolidine compound represented by the above chemicalformula (5) which is obtained by dehydration condensation of a carbonylcompound and an aminoalcohol compound, and

[0031] an epoxy resin.

[0032] A third invention is a one-pack moisture curable epoxy resincomposition comprising a silyl compound represented by the abovechemical formula (2) which has an epoxy group in an organic group, aketimine compound represented by the above chemical formula (4), and anepoxy resin.

[0033] A fourth invention is a one-pack moisture curable epoxy resincomposition comprising:

[0034] a vinyl carboxylate compound represented by the above chemicalformula (1),

[0035] one or two or more compounds selected from the group consistingof a silyl compound represented by the following chemical formula (6)and a silyl compound represented by the following chemical formula (7),

[0036] a ketimine compound represented by the above chemical formula (4)which is obtained by reaction of a carbonyl compound represented by theabove chemical formula (3) with an amine compound having a primary aminogroup, and

[0037] an epoxy resin:

[0038] wherein R₁₆, R₁₇, R₁₈ and R₁₉ are each an alkyl group and theymay be the same or different, and

[0039] n is an integer of 1 or more, and

[0040] wherein R₂₀ and R₂₁ are each an alkyl group and they may be thesame or different,

[0041] R₂₂ is an organic group, and

[0042] n is an integer of 1 to 3.

[0043] Since these silyl compounds have hydrolyzable alkoxysilyl groups,they can suppress reaction of the ketimine compound or oxazolidinecompound with water entering at the time of production or duringstorage. That is, the composition of the present invention is a one-packmoisture curable epoxy resin composition which does not requirelong-time curing so as to exhibit satisfactory strength.

BEST MODE FOR CARRYING OUT THE INVENTION

[0044] Hereinafter, an embodiment of the present invention will bedescribed in detail.

[0045] A vinyl carboxylate compound used in the present invention may beany compound represented by the following chemical formula (1) which hasa vinyl carboxylate group. Specific examples of the compound representedby the following chemical formula (1) include vinyl acetate, vinylbutyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate,vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl octoate, vinyl monochloroacetate, divinyl adipate,vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl benzoate, andvinyl cinnamate. It is needless to say that the vinyl carboxylate usedin the present invention is not limited to these vinyl carboxylates andtwo or more vinyl carboxylates may be used in combination.

[0046] wherein R₁, R₂, R₃ and R₄ are each a hydrogen atom or an organicgroup and they may be the same or different, and n is an integer of 1 ormore.

[0047] These vinyl carboxylates have high reactivity with an aminecompound. Therefore, an amine compound resulting from hydrolysis bywater entering during storage reacts with the vinyl carboxylate beforereacting with an epoxy resin so as to prevent an increase in viscositywhich is a problem in terms of quality.

[0048] A silyl compound used in the present invention and having anepoxy group in an organic group may be any compound represented by thefollowing chemical formula (2) which has an epoxy group and analkoxysilyl group in a molecule. Specific examples thereof includeγ-glycidoxypropyltrimethoxysilane represented by the following chemicalformula (8) and γ-glycidoxypropyltriethoxysilane represented by thefollowing chemical formula (9). Commercial products thereof areexemplified by KBM403 and KBE403 (products of SHIN-ETSU CHEMICAL CO.,LTD.), respectively, but are not limited to them. It is needless to saythat compounds represented by the following chemical formula (2) may beused in combination of two or more and may also be used in combinationwith a silyl compound represented by the above chemical formula (6) or(7):

[0049] wherein R₅ and R₆ are each an alkyl group and they may be thesame or different,

[0050] R₇ is an organic group having an epoxy group, and

[0051] n is an integer of 1 to 3, and

[0052] A ketimine compound used in the present invention is ahydrolyzable compound represented by the following chemical formula (4)which has a double bond between a carbon atom and a nitrogen atom. Theketimine compound is a compound obtained by reaction of a carbonylcompound in which same or different alkyl groups are bonded to a carbonatom in a carbonyl group with an amine compound having a primary aminogroup. The ketimine compound may be any compound having a structurerepresented by the chemical formula (4). Specific examples thereofinclude N,N′-di(1,3-dimethylbutylidene)-1,3-bisaminomethylcyclohexanerepresented by the following chemical formula (10) andN,N′-di(1,3-dimethylbutylidene)-meta-xylylene diamine represented by thefollowing chemical formula (11). These are a dehydration condensate of1,3-bisaminomethylcyclohexane and methyl isobutyl ketone and adehydration condensate of meta-xylylene diamine and methyl isobutylketone, respectively.

[0053] wherein R₁₀ is a residue excluding a primary amino group of anamine compound,

[0054] R₈ and R₉ are each selected from the group consisting of alkylgroups and they may be the same or different, and

[0055] n is an integer of 1 or more, and

[0056] A carbonyl compound which is used as a raw material of theketimine compound used in the present invention may be any carbonylcompound represented by the following chemical formula (3) in which sameor different alkyl groups are bonded to a carbon atom in a carbonylgroup. Specific examples thereof include acetone, methyl ethyl ketone,methyl isobutyl ketone, methyl isopropyl ketone, and methyl isopentylketone.

[0057] wherein R₈ and R₉ are each an alkyl group and they may be thesame or different.

[0058] An amine compound which is used as a raw material of the ketiminecompound used in the present invention may be any compound having aprimary amino group. Specific examples thereof include, but not limitedto, ethylene diamine, diethylene triamine,1,3-bisaminomethylcyclohexane, norbornane diamine, meta-xylylenediamine, isophorone diamine, bis(4-aminocyclohexyl)methane, a polyaminehaving a polyoxylene skeleton,N-β(aminoethyl)γ-aminopropyltrimethoxysilane,N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane,γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. Anamine compound having two or more primary amino groups in a molecule ispreferred since excellent mechanical strength is obtained.

[0059] The ketimine compound may be produced by any production method.For example, it can be produced by mixing the above carbonyl compoundwith the above amine compound in the absence of a solvent or in thepresence of a nonpolar solvent (such as hexane, cyclohexane, toluene orbenzene), subjecting the mixture to reflux under heating, and removingproduced water by azeotropy. As the carbonyl compound and amine compoundused as raw materials, one or two or more compounds selected from thegroup consisting of a variety of carbonyl compounds and one or two ormore compounds selected from the group consisting of a variety of aminecompounds may be used.

[0060] A specific oxazolidine compound used in the present invention isa hydrolyzable compound represented by the following chemical formula(5) which has an N atom and an O atom on the same carbon. Theoxazolidine compound is a compound obtained by reaction of a carbonylcompound having same or different alkyl groups bonded to a C atom in acarbonyl group with a secondary aminoalcohol compound. The specificoxazolidine compound may be any compound having a structure representedby the chemical formula (5):

[0061] wherein R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are each a hydrogen atom or anorganic group.

[0062] The carbonyl compound which is used as a raw material of theoxazolidine compound used in the present invention may be any carbonylcompound represented by the following chemical formula (3) which hassame or different alkyl groups bonded to a carbon atom in a carbonylgroup. Specific examples of such a carbonyl compound include acetone,methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone,methyl isopentyl ketone, diethyl ketone, dipropyl ketone, dibutylketone, ethyl propyl ketone, and ethyl butyl ketone.

[0063] wherein R₈ and R₉ are each an alkyl group and they may be thesame or different.

[0064] The aminoalcohol which is used as a raw material of theoxazolidine compound used in the present invention may be any compoundhaving a secondary ethanolamine structure. Specific examples thereofinclude, but not limited to, N-methylethanolamine, N-ethylethanolamine,N-propylethanolamine, N-ethyl-2-methylethanolamine, and diethanolamine.Of these, N-methylethanolamine and N-ethylethanolamine are preferredsince they have high reactivity with an epoxy resin.

[0065] The oxazolidine compound may be produced by any productionmethod. For example, it can be produced by mixing the above carbonylcompound with the above aminoalcohol compound in the absence of asolvent or in the presence of a nonpolar solvent (such as hexane,cyclohexane, toluene or benzene), subjecting the mixture to reflux underheating, and removing produced water by azeotropy. As the carbonylcompound and aminoalcohol compound used as raw materials, one or two ormore compounds selected from the group consisting of a variety ofcarbonyl compounds and one or two or more compounds selected from thegroup consisting of a variety of aminoalcohol compounds may be used.

[0066] Further, it is needless to say that two or more of the aboveketimine compounds and the above oxazolidine compounds may be used inthe one-pack epoxy resin composition. In addition, as long as curingproperties and storage stability are not impaired, other latenthardeners may also be used.

[0067] The epoxy resin may be any epoxy resin having an epoxy groupwhich is capable of reacting with the amine compound resulting fromhydrolysis of the ketimine compound or oxazolidine compound at the timeof its use. Illustrative examples of the epoxy resin include a biphenylepoxy resin, a bisphenol-A epoxy resin, a bisphenol-F epoxy resin, abisphenol-AD epoxy resin and a bisphenol-S epoxy resin which areobtained by reacting biphenyl, bisphenol A, bisphenol F, bisphenol ADand bisphenol S with epichlorhydrin, epoxy resins resulting fromhydrogenation or bromination of these epoxy resins, a glycidyl esterepoxy resin, a novolac epoxy resin, an urethane-modified epoxy resinhaving an urethane bond, a nitrogen-containing epoxy resin resultingfrom epoxidation of meta-xylene diamine or hydantoin, and arubber-modified epoxy resin containing a polybutadiene or NBR. The epoxyresin is not limited to these epoxy resins, and two or more epoxy resinsmay be used in combination.

[0068] The silyl compound used in the present invention may be anycompound represented by the following chemical formula (6) or (7) whichhas an alkoxysilyl group. Specific examples of the compound representedby the following chemical formula (6) include monomers such astetramethoxysilane, tetraethoxysilane and tetrabutoxysilane, andpolymers thereof. Specific examples of the compound represented by thefollowing chemical formula (7) include silane coupling agents havingorganic groups such as an alkyl group, a vinyl group, an epoxy group, anisocyanate group and a ketimine group. Specific examples of the silanecoupling agents include dimethyldimethoxysilane, methyltrimethoxysilane,methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane,γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-glycidoxypropylmethyldiethoxysilane, andγ-isocyanatepropyltriethoxysilane. It is needless to say that the silanecoupling agents are not limited to those enumerated above and two ormore silane coupling agents may be used in combination.

[0069] wherein R₁₆, R₁₇, R₁₈ and R₁₉ are each an alkyl group and theymay be the same or different, and

[0070] n is an integer of 1 or more, and

[0071] wherein R₂₀ and R₂₁ are each an alkyl group and they may be thesame or different,

[0072] R₂₂ is an organic group, and

[0073] n is an integer of 1 to 3.

[0074] As for the amount of the vinyl carboxylate based on the epoxyresin in the present invention, it is preferably 1 to 30 mol % per molof an epoxy group. When the amount is larger than the above range, thevinyl carboxylate hinders reaction with the epoxy resin by reacting withthe amine compound produced from the ketimine compound or oxazolidinecompound. When the amount is smaller than the above range, the vinylcarboxylate cannot fully react with the amine compound resulting fromhydrolysis of the ketimine compound or oxazolidine compound by a smallamount of water entering the composition during storage, so that storagestability cannot be improved. The amount preferably falls within theabove range since practical storage stability can be obtained. Theamount is more preferably 5 to 15 mol % since more ideal storagestability can be obtained.

[0075] As for the amount of the silyl compound represented by the abovechemical formula (2), (6) or (7) based on the epoxy resin used in thepresent invention, it varies according to the type of silyl compound tobe used. However, it is preferred that the amount of the silyl compoundbe not smaller than 10 parts by weight based on 100 parts by weight ofthe epoxy resin. When the amount is lower than the above range, theamount of the silyl compound is too small to fully consume a smallamount of water entering the composition system during storage and tosuppress hydrolysis of the ketimine compound or oxazolidine compound, sothat practical storage stability cannot be obtained. The amountpreferably falls within the above range since practical storagestability can be obtained. The amount is more preferably not smallerthan 30 parts by weight since the most superior storage stability can beobtained.

[0076] The mixing ratio of the ketimine compound and the epoxy compoundin the present invention is determined according to the equivalent ofactive hydrogen in the amine compound resulting from hydrolysis of theketimine compound and the equivalent of an epoxy group in the epoxycompound. That is, the equivalent of the active hydrogen in the aminecompound resulting from the hydrolysis of the ketimine compound ispreferably 0.5 to 2.0 times as much as the equivalent of the epoxygroup. When the mixing ratio is lower than the above range, the epoxygroup becomes excessive, crosslinking in a cured product does notproceed satisfactorily, and practical mechanical strength cannot beobtained. When the mixing ratio is higher than the above range, theamine compound resulting from the hydrolysis becomes excessive, that is,the active hydrogen becomes excessive, and in this case as well, due tothe same reason, practical mechanical strength cannot be obtained. Themixing ratio preferably falls within the above range since a crosslinkedstructure with practical mechanical strength can be obtained. The mixingratio is more preferably 0.8 to 1.2 times since an ideal crosslinkedstructure with better mechanical strength as an adhesive composition canbe obtained.

[0077] As for the amount of the oxazolidine compound based on the epoxycompound in the present invention, it is preferably 10 to 40 parts byweight based on 100 parts by weight of the epoxy resin having a weightper epoxide of 190. When the amount is lower than the above range, theepoxy group becomes excessive, crosslinking in a cured product does notproceed satisfactorily, and practical mechanical strength cannot beobtained. When the amount is higher than the above range, the aminecompound resulting from hydrolysis becomes excessive, that is, activehydrogen becomes excessive, and in this case as well, due to the samereason, practical mechanical strength cannot be obtained. The amountpreferably falls within the above range since a crosslinked structurewith practical mechanical strength can be obtained. The amount is morepreferably 20 to 30 parts by weight since an ideal crosslinked structurewith better mechanical strength as an adhesive composition can beobtained.

[0078] In addition to the foregoing compounds, the composition of thepresent invention may also contain a filler such as calcium carbonate ortitanium oxide, a coupling agent such as epoxysilane or vinylsilane, aplasticizer, a thixotropy imparting agent, a pigment, a dye, an ageresistor, an antioxidant, an antistatic agent, a flame retardant, anadhesion imparting agent, a dispersant, a solvent and the like in suchan amount that does not impair the effect of the present invention. Inthis case, it gives a favorable result on storage stability that theinfluence of water in the above components which may be contained isremoved as much as possible.

[0079] A production method of the composition of the present inventionis not particularly limited but is preferably produced by fully kneadingits raw materials under a nitrogen atmosphere or a reduced pressure byuse of a stirrer such as a mixer. An example of the production method isas follows. An epoxy resin is put in a closed processing furnaceequipped with a stirrer, a condenser, a heater, a low-pressuredehydrator and a nitrogen current ventilator. Using the nitrogen currentventilator, a modifier or an additive is added to the epoxy resin asdesired and they are mixed uniformly under nitrogen reflux. Thereafter,one or two or more compounds selected from the group consisting of aketimine compound and an oxazolidine compound are added eventually andmixed uniformly so as to obtain a one-pack moisture curable adhesivecomposition. Then, the one-pack moisture curable adhesive composition isput in a nitrogen-substituted closed container so as to become a finalproduct. When water is contained in the modifier or additive, thecomposition is liable to be cured and storage stability is liable todeteriorate during storage. Hence, it is preferable to remove the waterfrom the modifier or additive in advance. The water may be removedbefore addition of the modifier or additive or removed by means ofheating or decompression after they are added to the epoxy resin.

EXAMPLES

[0080] Hereinafter, the present invention will be described based onExamples. The present invention, however, shall not be limited to theExamples.

[0081] [Synthesis of Ketimine Compound]

Synthesis Example 1

[0082] 142 g of 1,3-bisaminomethylcyclohexane (product of Mitsubishi GasChemical Company Inc., trade name: 1,3-BAC) and 300 g of methyl isobutylketone corresponding to 3 time mole equivalents were put in a flask and,while produced water was removed by azeotropy, they were allowed toreact for 20 hours at temperatures (120 to 150° C.) at which toluene andmethyl isobutyl ketone were refluxed. Then, excessive methyl isobutylketone and toluene were distilled out so as to obtain a ketiminecompound A.

Synthesis Example 2

[0083] A ketimine compound B was obtained in the same manner as inSynthesis Example 1 except that 154 g of norbornane diamine (product ofMitsui Chemicals, Inc., trade name: NBDA) was used as an amine compound.

Example 1

[0084] 100 parts by weight of epoxy resin (product of YUKA SHELL EPOXYCO., LTD. (corporate name change: Japan Epoxy Resins), trade name:Epikote 828), 40 parts by weight of heavy calcium carbonate (product ofNITTO FUNKA KOGYO CO., LTD., trade name: NS100) and 80 parts by weightof surface-treated calcium carbonate (product of MARUO CALCIUM CO.,LTD., trade name: MS700) were heated at 100° C. under a reduced pressureof 15 Torr for 2 hours and stirred and mixed until the mixture becameuniform. After the mixture became uniform, it was cooled to roomtemperature. Then, to the mixture, 30 parts by weight of an oxazolidinecompound (product of San-Apro Ltd., trade name: MS-PLUS) as a hardenerfor the epoxy resin and 6.6 parts by weight of vinyl butyrate as astabilizer were added, and the resulting mixture was stirred under areduced pressure so as to obtain a one-pack moisture curable epoxy resincomposition.

Example 2

[0085] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 1 except that 40 parts by weight ofepoxy silane coupling agent (product of SHIN-ETSU CHEMICAL CO., LTD.,trade name: KBM403) was used in place of vinyl butyrate as a stabilizer.

Example 3

[0086] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 1 except that 45 parts by weight of theketimine compound A was used in place of the oxazolidine compound as alatent hardener.

Example 4

[0087] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 2 except that 45 parts by weight of theketimine compound A was used in place of the oxazolidine compound as alatent hardener.

Example 5

[0088] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 4 except that 6.6 parts by weight ofvinyl butyrate was added as a stabilizer.

Example 6

[0089] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 5 except that the ketimine compound Bwas used in place of the ketimine compound A as a latent hardener.

Example 7

[0090] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 5 except that 10 parts by weight ofoxazolidine compound as a latent hardener was added in place of reducingthe amount of the ketimine compound A as a latent hardener to 30 partsby weight.

Example 8

[0091] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 3 except that 40 parts by weight ofethyl silicate (Toshiba Silicones Co., Ltd., trade name: TSL8124) wasadded as a stabilizer.

Example 9

[0092] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 8 except that 13.1 parts by weight ofvinyl laurate was used in place of vinyl butyrate as a stabilizer.

Comparative Example 1

[0093] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 1 except that vinyl butyrate was notused.

Comparative Example 2

[0094] A one-pack moisture curable epoxy resin composition was obtainedin the same manner as in Example 3 except that vinyl butyrate was notused.

[0095] The following tests were conducted by use of the one-packmoisture curable epoxy resin compositions of Examples 1 to 9 andComparative Examples 1 and 2. The results of Examples 1 to 9 andComparative Examples 1 and 2 are shown in Tables 1 and 2. TABLE 1 Ex.1Ex.2 Ex.3 Ex.4 Ex.5 Ex.6 Epoxy Resin Epikote 828 100 100 100 100 100 100Heavy Calcium Carbonate NS100 40 40 40 40 40 40 Treated CalciumCarbonate MS700 80 80 80 80 80 80 Oxazolidine Compound MS-PLUS 30 30Ketimine Compound A 1,3-BAC-MIBK 45 45 45 Ketimine Compound B NBDA-MIBK45 Vinyl Ester Compound A Vinyl Butyrate 6.6 6.6 6.6 6.6 Vinyl EsterCompound B Vinyl Laurate Ethyl Silicate TSL8124 Epoxysilane CompoundKBM403 40 40 40 40 Adhesive Property 23° C., after 7 days 5.8 5.6 7.57.9 9.2 8.9 (Mortar Bending Adhesive Cohesive Cohesive Cohesive MortarMortar Mortar Strength) Failure Failure Failure Failure Failure FailurePartial Mortar lower row: condition of Failure failure Deep Curability23° C., after 7 days Good Excellent Acceptable Good Good Good Stability20° C., after 2 Excellent Excellent Excellent Excellent ExcellentExcellent months 200C, after 4 Excellent Excellent Good Good ExcellentExcellent months 20° C., after 6 Acceptable Acceptable AcceptableAcceptable Excellent Excellent months

[0096] TABLE 2 Ex.7 Ex.8 Ex.9 C.Ex.1 C.Ex.2 Epoxy Resin Epikote 828 100100 100 100 100 Heavy Calcium Carbonate NS100 40 40 40 40 40 TreatedCalcium Carbonate MS700 80 80 80 80 80 Oxazolidine Compound MS-PLUS 1030 Ketimine Compound A 1,3-BAC-MIBK 30 45 45 45 Ketimine Compound BNBDA-MIBK Vinyl Ester Compound A Vinyl Butyrate 6.6 6.6 Vinyl EsterCompound B Vinyl Laurate 13.1 Ethyl Silicate TSL8124 40 40 EpoxysilaneCompound KBM403 40 Adhesive Property 23° C., after 7 days 8.0 6.5 6.15.5 6.4 (Mortar Bending Adhesive Mortar Cohesive Cohesive CohesiveCohesive Strength) Failure Failure Failure Failure Failure upper row:N/mm² Partial Partial Partial lower row: condition of Mortar MortarMortar failure Failure Failure Failure Deep Curability 23° C., after 7days Good Acceptable Acceptable Good Acceptable Stability 20° C., after2 Excellent Excellent Excellent Unacceptable Unacceptable months 20° C.,after 4 Excellent Excellent Excellent Unacceptable Unacceptable months20° C., after 6 Excellent Excellent Excellent Unacceptable Unacceptablemonths

[0097] (Adhesive Property)

[0098] An adhesive property was measured in accordance with JIS A6024(refer to adhesive property) of a mortar bending adhesive test undervarious curing conditions. That is, it was measured in accordance with astandard condition (curing at 23° C. for 7 days) of an adhesive strengthtest in JIS A6024 (injection epoxy resin for construction repairing).Its unit was N/mm², and a condition of failure at that time was shown.

[0099] (Deep Curability)

[0100] The one-pack moisture curable epoxy resin composition was chargedinto a deep container without trapping air therein and allowed to cureat 23° C. for 1 week. The thickness of a cured product layer excludingthe uncured composition was measured. The thickness of the cured productlayer was compared and rated on the following four-rank scale of“Excellent”, “Good”, “Acceptable” and “Unacceptable”.

[0101] Excellent: 2.0≦Thickness (mm) of cured product after cured at 23°C. for 7 days.

[0102] Good: 1.0≦Thickness (mm) of cured product after cured at 23° C.for 7 days <2.0

[0103] Acceptable: 0.5≦Thickness (mm) of cured product after cured at23° C. for 7 days <1.0

[0104] Unacceptable: Thickness (mm) of cured product after cured at 23°C. for 7 days <0.5

[0105] To rate the characteristic value of the deep curability in thepresent invention, a characteristic value rated as “Excellent” is themost excellent from a practical standpoint, followed by one rated as“Good”. A characteristic value rated as “Acceptable” is inferior tothose rated as “Excellent” and “Good” but still has practicability.However, “Unacceptable” represents a characteristic value which is themost inferior and lacks practicability.

[0106] (Stability)

[0107] Stability was measured by placing a sample in a closed cartridgeand measuring its viscosity when stored at various temperatureconditions. That is, the one-pack moisture curable epoxy resincomposition was filled and sealed in the cartridge and left to stand at23° C. for various time periods, and then its viscosity was measured.Then, stability was compared with its viscosity immediately afterpreparation and rated on the following four-rank scale of “Excellent”,“Good”, “Acceptable” and “Unacceptable”. The viscosity was measured at23° C. by use of a BH-type viscometer at 10 r/min.

[0108] Excellent: (viscosity after left to stand)/(viscosity immediatelyafter preparation)≦1.5

[0109] Good: 1.5<(viscosity after left to stand)/(viscosity immediatelyafter preparation)≦2

[0110] Acceptable: 2<(viscosity after left to stand)/(viscosityimmediately after preparation)≦3

[0111] Unacceptable: 3<(viscosity after left to stand)/(viscosityimmediately after preparation)

[0112] To rate the characteristic value of the stability in the presentinvention, a characteristic value rated as “Excellent” is the mostexcellent from a practical standpoint, followed by one rated as “Good”.A characteristic value rated as “Acceptable” is inferior to those ratedas “Excellent” and “Good” but still has practicability. However,“Unacceptable” represents a characteristic value which is the mostinferior and lacks practicability.

[0113] It is obvious from comparison of Examples 1 and 2 withComparative Example 1 that the one-pack moisture curable epoxy resincompositions of the Examples show adhesive properties equal to that ofthe one-pack moisture curable epoxy resin composition of the ComparativeExample. Further, it is understood that since the one-pack moisturecurable epoxy resin compositions of the Examples show better storagestability than the one-pack moisture curable epoxy resin composition ofthe Comparative Example, only storage stability is improved withoutimpairing the adhesive properties.

[0114] Further, it is obvious from comparison of Examples 3 to 9 withComparative Example 2 that the one-pack moisture curable epoxy resincompositions of the Examples show adhesive properties which are equal toor better than that of the one-pack moisture curable epoxy resincomposition of the Comparative Example. Further, it is understood thatsince the one-pack moisture curable epoxy resin compositions of theExamples show better storage stability than the one-pack moisturecurable epoxy resin composition of the Comparative Example, only storagestability is improved without impairing the adhesive properties. Inaddition, as is obvious from Example 5 to 7, by concurrent use of thevinyl carboxylate and the epoxysilane as stabilizers, storage stabilityand inner curability can be improved without impairing curingproperties.

POSSIBILITY OF INDUSTRIAL UTILIZATION

[0115] As described above, the one-pack moisture curable epoxy resincomposition according to the present invention is a room-temperaturecurable adhesive composition which has balanced contradictoryproperties, i.e., improving storage stability significantly withoutimpairing quick curability. Accordingly, the one-pack moisture curableepoxy resin composition according to the present invention is suitablefor being effectively used in applications in which a conventionaltwo-pack epoxy resin has been used such as an adhesive, putty material,paint, coating material and potting material using the composition.

1. A one-pack moisture curable epoxy resin composition comprising: (a)one or two or more compounds selected from the group consisting of avinyl carboxylate compound represented by the following chemical formula(1) and a silyl compound represented by the following chemical formula(2) which has an epoxy group in an organic group, (b) one or two or morecompounds selected from the group consisting of a ketimine compoundrepresented by the following chemical formula (4) which is obtained byreaction of a carbonyl compound represented by the following chemicalformula (3) with an amine compound having a primary amino group and anoxazolidine compound represented by the following chemical formula (5)which is obtained by dehydration condensation of a carbonyl compound andan aminoalcohol compound, and (c) an epoxy resin:

wherein R₁, R₂, R₃ and R₄ are each a hydrogen atom or an organic groupand they may be the same or different, and n is an integer of 1 or more,

wherein R₅ and R₆ are each an alkyl group and they may be the same ordifferent, R₇ is an organic group having an epoxy group, and n is aninteger of 1 to 3,

wherein R₈ and R₉ are each an alkyl group and they may be the same ordifferent,

wherein R₁₀ is a residue excluding a primary amino group of aminecompound, R₈ and R₉ are each an alkyl group and they may be the samedifferent, and n is an integer of 1 or more, and

wherein R₁₁, R₁₂, R₁₃, R₁₄ and R₁₅ are each a hydrogen atom or anorganic group.
 2. A one-pack moisture curable epoxy resin compositioncomprising: (a) a vinyl carboxylate compound represented by the abovechemical formula (1), (b) one or two or more compounds selected from thegroup consisting of a ketimine compound represented by the abovechemical formula (4) which is obtained by reaction of a carbonylcompound represented by the above chemical formula (3) with an aminecompound having a primary amino group and an oxazolidine compoundrepresented by the above chemical formula (5) which is obtained bydehydration condensation of a carbonyl compound and an aminoalcoholcompound, and (c) an epoxy resin.
 3. A one-pack moisture curable epoxyresin composition comprising: a silyl compound represented by the abovechemical formula (2) which has an epoxy group in an organic group, aketimine compound represented by the above chemical formula (4), and anepoxy resin.
 4. A one-pack moisture curable epoxy resin compositioncomprising: a vinyl carboxylate compound represented by the abovechemical formula (1), one or two or more compounds selected from thegroup consisting of a silyl compound represented by the followingchemical formula (6) and a silyl compound represented by the followingchemical formula (7), a ketimine compound represented by the abovechemical formula (4) which is obtained by reaction of a carbonylcompound represented by the above chemical formula (3) with an aminecompound having a primary amino group, and an epoxy resin:

wherein R₁₆, R₁₇, R₁₈ and R₁₉ are each an alkyl group and they may bethe same or different, and n is an integer of 1 or more, and

wherein R₂₀ and R₂₁ are each an alkyl group and they may be the same ordifferent, R₂₂ is an organic group, and n is an integer of 1 to 3.